Systems and methods for controlling planetary transmission arrangements for marine propulsion devices

ABSTRACT

Transmission systems and methods are for a marine propulsion device having an internal combustion engine that drives a propulsor. An input shaft is driven into rotation at a non-zero first rotational speed by the internal combustion engine. An output shaft drives the propulsor into rotation at a non-zero second rotational speed. A planetary gearset transfers power from the input shaft to the output shaft. A band brake is on the planetary gearset. Actuation of the band brake effects a gear change in the planetary gearset. A band brake actuator actuates the band brake to effect the gear change. A controller controls the band brake actuator. Based upon one or more operational characteristics of the marine propulsion device the controller is programmed to control the band brake actuator so that the second rotational speed is less than the first rotational speed.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a divisional of U.S. application Ser. No.14/605,393, filed Jan. 26, 2015, of which application is herebyincorporated by reference in its entirety.

FIELD

The present disclosure relates to marine propulsion devices, and moreparticularly to transmission arrangements for marine propulsion devicesand to systems and methods for controlling transmission arrangements formarine propulsion devices.

BACKGROUND

The following U.S. Patents are incorporated herein by reference:

U.S. Pat. No. 6,350,165 discloses an inboard/outboard powered watercraftthat incorporates a transmission in its vertical drive unit forproviding two forward speeds plus reverse. The transmission is packagedto fit within the vertical drive unit by incorporating a bevel gearapparatus. In one embodiment, the transmission also includes a planetarygear apparatus together with two hydraulic clutches and a ring gearbrake. In a second embodiment, three hydraulic clutches are utilizedwith bevel gears alone to provide the two forward and reverse speeds.

U.S. Pat. No. 6,435,923 discloses a two-speed transmission with reversegearing for a watercraft. The transmission is disposed in the gimbalhousing passing through the transom of the watercraft. A pair ofplanetary gears share a common ring gear to provide both forward-reverseand first-second gearing in a very compact package. The transmissionhousing may be formed in two portions, a first housing containing theforward-reverse gear mechanisms and a second housing containing thefirst-second gear mechanism. The transmission output shaft is connectedto the drive shaft of a vertical drive unit by a double universal jointthat may be replaced without disassembling the transmission components.

U.S. Pat. No. 7,891,263 discloses a two speed transmission systemmounted for driving a marine craft. The transmission system comprises aninput shaft coupled in direct connection with a driveshaft of an engineof the marine craft; an output shaft coaxial with the input shaftcoupled in direct connection with a driveline of the marine craft; afirst gear train for transmitting drive at a fixed first gear ratio; asecond gear train for transmitting drive at a fixed second gear ratio; afirst friction clutch operable to engage/disengage the first gear train;and a second friction clutch operable to engage/disengage the secondgear train. Shifting between the first gear ratio and the second gearratio one of the friction clutches is disengaged using controlledslippage while the other friction clutch is engaged using controlledslippage.

U.S. Pat. No. 7,942,712 discloses an outboard motor that includes apower source, a boat propulsion section, a shift position switchingmechanism, a clutch actuator, and a control device. The shift positionswitching mechanism switches among a first shift position in which afirst clutch is engaged and a second clutch is disengaged, a secondshift position in which the first clutch is disengaged and the secondclutch is engaged, and a neutral position in which both the first clutchand the second clutch are disengaged. When a gear shift is to be madefrom the first shift position to the second shift position, the controlsection causes the clutch actuator to gradually increase an engagementforce of the second clutch. The outboard motor reduces the load to beapplied to the power source and the power transmission mechanism at thetime of a gear shift in a boat propulsion system including anelectronically controlled shift mechanism.

U.S. Pat. No. 8,109,800 discloses a transmission device that includeshydraulic type transmission mechanisms arranged to change the speed orthe direction of rotation of an engine, and hydraulic pressure controlvalves arranged to control hydraulic pressure supplied to the hydraulictype transmission mechanisms. The hydraulic pressure control valves aredisposed on one side or the other side in the watercraft widthdirection. The transmission device provides an outboard motor capable ofsecuring cooling characteristics of a hydraulic pressure control valvewithout incurring complexity in structure and increase in cost.

U.S. Pat. No. 8,157,694 discloses an outboard motor having a powertransmission mechanism for transmitting power of an engine to apropeller. The power transmission mechanism has a transmission ratiochanging unit having a planetary gear train including a sun gear,planetary gears, and an internal gear. The internal gear is connected toan input side shaft on the engine side. The planetary gears areconnected to an output side shaft on the propeller side. The sun gear isconnected to a stationary portion via a one-way clutch. The planetarygears and the internal gear and/or the sun gear are connected by anon-off clutch. When the on-off clutch is disengaged, the one-way clutchis engaged and the speed from the input side shaft is outputted from theoutput side shaft with a reduced speed. When the on-off clutch isengaged, the speed from the input side shaft is outputted from theoutput side shaft with the same speed.

U.S. Pat. No. 8,277,270 discloses a boat propulsion unit that includes apower source, a propeller, a shift position switching mechanism, acontrol device, and a retention switch. The propeller is driven by thepower source to generate propulsive force. The shift position switchingmechanism has an input shaft connected to a side of the power source, anoutput shaft connected to a side of the propeller, and clutches thatchange a connection state between the input shaft and the output shaft.A shift position of the shift position switching mechanism is switchedamong forward, neutral, and reverse by engaging and disengaging theclutches. The control device adjusts an engagement force of theclutches. The retention switch is connected to the control device. Whenthe retention switch is turned on by an operator, the control devicecontrols the engagement force of the clutches to retain a hull in apredefined position. The boat propulsion unit provides a boat propulsionunit that can accurately retain a boat at a fixed point.

U.S. Pat. No. 8,317,556 discloses a boat propulsion system that includesa power source, a propulsion section, a shift position switchingmechanism arranged to switch among a first shift position, a secondshift position, and a neutral position, a gear ratio switchingmechanism, an actuator, and a control section. When switching is to beperformed from the neutral position to the first shift position and thehigh-speed gear ratio, the control section is arranged to cause theactuator to, maintain the low-speed gear ratio, switch to the firstshift position, and then establish the high-speed gear ratio when thecurrent gear ratio of the gear ratio switching mechanism is thelow-speed gear ratio, and cause the actuator to establish the low-speedgear ratio before switching to the first shift position, switch to thefirst shift position, and then establish the high-speed gear ratio whenthe current gear ratio of the gear ratio switching mechanism is thehigh-speed gear ratio. This arrangement improves the durability of apower source and a power transmission mechanism in a boat propulsionsystem including an electronically controlled shift mechanism.

U.S. patent application Ser. No. 14/585,872 discloses a transmission fora marine propulsion device having an internal combustion engine thatdrives a propulsor for propelling a marine vessel in water. An inputshaft is driven into rotation by the engine. An output shaft drives thepropulsor into rotation. A forward planetary gearset that connects theinput shaft to the output shaft so as to drive the output shaft intoforward rotation. A reverse planetary gearset that connects the inputshaft to the output shaft so as to drive the output shaft into reverserotation. A forward brake engages the forward planetary gearset in aforward gear wherein the forward planetary gearset drives the outputshaft into the forward rotation. A reverse brake engages the reverseplanetary gearset in a reverse gear wherein the reverse planetarygearset drives the output shaft into the reverse rotation.

U.S. patent application Ser. No. 14/258,516 discloses a system thatcontrols the speed of a marine vessel including first and secondpropulsion devices that produce first and second thrusts to propel themarine vessel. A control circuit controls orientation of the first andsecond propulsion devices about respective steering axes to controldirections of the first and second thrusts. A first user input device ismoveable between a neutral position and a non-neutral detent position.When a second user input device is actuated while the first user inputdevice is in the detent position, the control circuit does one or moreof the following so as to control the speed of the marine vessel: variesa speed of a first engine of the first propulsion device and a speed ofa second engine of the second propulsion device; and varies one or morealternative operating conditions of the first and second propulsiondevices.

U.S. patent application Ser. No. 14/574,953 discloses a system forcontrolling a rotational speed of a marine internal combustion enginehaving a first operator input device for controlling a speed of theengine in a trolling mode, in which the engine operates at a firstoperator-selected engine speed so as to propel a marine vessel at afirst non-zero speed. A second operator input device controls the enginespeed in a non-trolling mode, in which the engine operates at a secondoperator-selected engine speed so as to propel the marine vessel at asecond non-zero speed. A controller is in signal communication with thefirst operator input device, the second operator input device, and theengine. In response to an operator request to transition from thetrolling mode to the non-trolling mode, the controller determineswhether to allow the transition based on the second operator-selectedengine speed and a current engine speed.

U.S. Pat. No. 7,267,068 discloses a marine vessel maneuvered byindependently rotating first and second marine propulsion devices abouttheir respective steering axes in response to commands received from amanually operable control device, such as a joystick. The marinepropulsion devices are aligned with their thrust vectors intersecting ata point on a centerline of the marine vessel and, when no rotationalmovement is commanded, at the center of gravity of the marine vessel.Internal combustion engines are provided to drive the marine propulsiondevices. The steering axes of the two marine propulsion devices aregenerally vertical and parallel to each other. The two steering axesextend through a bottom surface of the hull of the marine vessel.

U.S. Pat. No. 7,305,928 discloses a vessel positioning system thatmaneuvers a marine vessel in such a way that the vessel maintains itsglobal position and heading in accordance with a desired position andheading selected by the operator of the marine vessel. When used inconjunction with a joystick, the operator of the marine vessel can placethe system in a station keeping enabled mode and the system thenmaintains the desired position obtained upon the initial change in thejoystick from an active mode to an inactive mode. In this way, theoperator can selectively maneuver the marine vessel manually and, whenthe joystick is released, the vessel will maintain the position in whichit was at the instant the operator stopped maneuvering it with thejoystick.

U.S. Pat. No. 7,561,886 discloses a method provided by which a positionof a marine vessel can be determined relative to a stationary object,such as a dock. Two position sensors are attached to a marine vessel anda microprocessor, onboard the marine vessel, computes various distancesand angular relationships between the position sensors on the marinevessel and stationary transponders attached to the fixed device, such asa dock. The various dimensions and angular relationships allow acomplete determination regarding the location and attitude of a marinevessel relative to the dock. This information can then be used by amaneuvering program to cause the marine vessel to be berthed at aposition proximate the dock.

U.S. Pat. No. 8,478,464 discloses systems and methods for orienting amarine vessel so as to enhance available thrust in a station keepingmode. A control device having a memory and a programmable circuit isprogrammed to control operation of a plurality of marine propulsiondevices to maintain orientation of a marine vessel in a selected globalposition. The control device is programmed to calculate a direction of aresultant thrust vector associated with the plurality of marinepropulsion devices that is necessary to maintain the vessel in theselected global position. The control device is programmed to controloperation of the plurality of marine propulsion devices to change theactual heading of the marine vessel to align the actual heading with thethrust vector.

U.S. Pat. No. 8,777,681 discloses systems for maneuvering a marinevessel that comprise a plurality of marine propulsion devices that aremovable between an aligned position to achieve of movement of the marinevessel in a longitudinal direction and/or rotation of the marine vesselwith respect to the longitudinal direction and an unaligned position toachieve transverse movement of the marine vessel with respect to thelongitudinal direction. A controller has a programmable circuit andcontrols the plurality of marine propulsion devices to move into theunaligned position when a transverse movement of the marine vessel isrequested and to thereafter remain in the unaligned position after thetransverse movement is achieved. Methods of maneuvering a marine vesselcomprise requesting transverse movement of the marine vessel withrespect to a longitudinal direction and operating a controller to orienta plurality of marine propulsion devices into an unaligned position toachieve the transverse movement, wherein the plurality of marinepropulsion devices remain in the unaligned position after the transversemovement is achieved.

U.S. Pat. No. 8,924,054 discloses systems and methods for orienting amarine vessel having a marine propulsion device. A control circuitcontrols operation of the marine propulsion device. A user input deviceinputs to the control circuit a user-desired global position and auser-desired heading of the marine vessel. The control circuitcalculates a position difference between the user-desired globalposition and an actual global position of the marine vessel and controlsthe marine propulsion device to minimize the position difference. Thecontrol circuit controls the marine propulsion device to orient anactual heading of the marine vessel towards the user-desired globalposition when the position difference is greater than a threshold. Whenthe position difference is less than the threshold, the control circuitcontrols the marine propulsion device to minimize a difference betweenthe actual heading and the user-desired heading while minimizing theposition difference.

SUMMARY

This Summary is provided to introduce a selection of concepts that arefurther described herein below in the Detailed Description. This Summaryis not intended to identify key or essential features of the claimedsubject matter, nor is it intended to be used as an aid in limiting thescope of the claimed subject matter.

In certain examples, transmission systems are for a marine propulsiondevice having an internal combustion engine that drives a propulsor. Aninput shaft is driven into rotation at a non-zero first rotational speedby the internal combustion engine. An output shaft drives the propulsorinto rotation at a non-zero second rotational speed. A planetary gearsettransfers power from the input shaft to the output shaft. A band brakeis on the planetary gearset. Actuation of the band brake effects a gearchange in the planetary gearset between (1) a neutral gear whereinrotation of the input shaft does not cause rotation of the output shaftand (2) at least one of a forward gear wherein rotation of the inputshaft causes forward rotation of the output shaft and a reverse gearwherein rotation of the input shaft causes reverse rotation of theoutput shaft. A band brake actuator actuates the band brake to effectthe gear change. A controller controls the band brake actuator. Basedupon one or more operational characteristics of the marine propulsiondevice the controller is programmed to control the band brake actuatorso that the second rotational speed is less than the first rotationalspeed. Corresponding methods for controlling transmission systems areprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is described with reference to the followingFigures. The same numbers are used throughout the Figures to referencelike features and like components.

FIG. 1 is a side view of an outboard marine propulsion device.

FIG. 2 is a perspective view of a transmission for the outboard marinepropulsion device.

FIGS. 3-6 are exploded views of the transmission.

FIG. 7 is a top view of a brake for the transmission.

FIG. 8 is a perspective view of a band brake for the transmission.

FIG. 9 is a perspective view of another type of band brake for thetransmission.

FIG. 10 is a view of section 10-10 taken in FIG. 2, showing thetransmission in neutral gear.

FIG. 11 is a view of section 10-10 taken in FIG. 2, showing thetransmission in forward gear.

FIG. 12 is a view of section 10-10 taken in FIG. 2, showing thetransmission in reverse gear.

FIG. 13 is a diagram of an exemplary system according to the presentdisclosure.

FIGS. 14-22 are schematic and graphical depictions showing operationalmodes of exemplary systems according to the present disclosure.

FIG. 23 is a flow chart of an exemplary method according to the presentdisclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an outboard marine propulsion device 10 for propelling amarine vessel 12 in water. The outboard marine propulsion device 10 isconnected to the transom 14 of the marine vessel 12 by a transom bracket16. As is conventional, the outboard marine propulsion device 10includes an internal combustion engine 18 located within an uppercowling 20. The engine 18 causes rotation of a drive shaft 22 thatextends downwardly from the engine 18 through a drive shaft housing 24.A transmission 26 relays rotational force from the drive shaft 22 to apropulsor shaft 28 located in a propulsor shaft housing 30. Thetransmission 26 is located in or above a gearcase housing 32, which isdisposed beneath the drive shaft housing 24. Rotation of the propulsorshaft 28 causes rotation of a propulsor 34, which in this exampleincludes counter rotating propellers 36. The type of propulsor 34 canvary from that which is shown, and in other examples can include singleor multiple propellers or single or multiple impellers, and/or the like.

Embodiments of the transmission 26 are shown in FIGS. 2-12. Referring toFIGS. 2-6, the transmission 26 includes an input shaft 38 that is driveninto rotation by the engine 18. The input shaft 38 can be the driveshaft 22 or an extension of the drive shaft 22 such that rotation of thedrive shaft 22 causes concurrent rotation of the input shaft 38. Thetransmission 26 also includes an output shaft 40 that is connected tothe propulsor shaft 28 via for example a conventional gearset (notshown) such that rotation of the output shaft 40 causes concurrentrotation of the propulsor shaft 28. The input shaft 38 and output shaft40 are connected together by forward and reverse planetary gearsets 42,44 such that the input shaft 38 and output shaft 40 are coaxiallyaligned.

As will be described in more detail herein below, the forward planetarygearset 42 connects the input shaft 38 to the output shaft 40 so as todrive the output shaft 40 into forward rotation. The reverse planetarygearset 44 connects the input shaft 38 to the output shaft 40 so as todrive the output shaft 40 into reverse rotation. The forward and reverseplanetary gearsets 42, 44 both provide the same speed reduction from theinput shaft 38 to the output shaft 40. In one non-limiting example, thenominal reduction is 1.68:1. A forward brake 46 engages the forwardplanetary gearset 42 in forward gear so as to drive the output shaft 40into the forward rotation. A reverse brake 48 engages the reverseplanetary gearset 44 in reverse gear so as to drive the output shaft 40into the reverse rotation. Actuation of neither of the forward brake 46and reverse brake 48 actuates a neutral gear wherein the output shaft 40is disconnected from the input shaft 38.

Referring to FIGS. 3-6, the forward planetary gearset 42 includes aforward ring gear 50 that is fixed to and rotates with the input shaft38. The forward ring gear 50 and the input shaft 38 can be formedtogether as one piece or can be separate pieces that are connectedtogether. The forward ring gear 50 includes a radially inwardly facinggear surface 52. The forward planetary gearset 42 also includes aforward sun gear 54 that is disposed on the output shaft 40. The forwardsun gear 54 has a radially outwardly facing gear surface 56 and aradially inwardly facing bearing surface 58. The radially inwardlyfacing bearing surface 58 bears on the output shaft 40 such that theforward sun gear 54 is rotatable with respect to the output shaft 40,and vice verse. The type of bearing surface can vary and in this exampleincludes roller bearings 59. The forward planetary gearset 42 furtherincludes a forward brake drum 60 that rotates with the forward sun gear54. The forward brake drum 60 can be formed as one component with theforward sun gear 54 or the forward brake drum 60 can be a separatecomponent that is attached to the forward sun gear 54.

The forward planetary gearset 42 further includes a plurality of forwardplanet gears 62 that are rotatable about their own center axis 64 andthat are radially disposed between the forward ring gear 50 and theforward sun gear 54. Each forward planet gear 62 has a radiallyoutwardly facing gear surface 66 that is engaged with the radiallyinwardly facing gear surface 52 of the forward ring gear 50 and theradially outwardly facing gear surface 56 of the forward sun gear 54.The forward planetary gearset 42 further includes a forward carrier 68that retains the plurality of forward planet gears 62 so that theforward planet gears 62 are rotatable about their own center axis 64.The forward carrier 68 is fixed to and rotates with the output shaft 40and is rotatable with respect to the forward ring gear 50 and theforward sun gear 54. The manner of connection between the forwardcarrier 68 and the output shaft 40 can vary. In this example, a firstplurality of splines 70 are formed on a radially inwardly facing surface71 of the forward carrier 68 and engage with a second plurality ofsplines 72 on a radially outer surface 73 of the output shaft 40.

The reverse planetary gearset 44 includes a reverse sun gear 74 that isfixed to and rotates with the input shaft 38. The reverse sun gear 74can be formed as one component with the input shaft 38 or formedseparately from and connected to the input shaft 38. The reverse sungear 74 has a radially outwardly facing gear surface 76. The reverseplanetary gearset 44 also has a reverse ring gear 78 that is fixed toand rotates with the forward carrier 68. The reverse ring gear 78 andthe forward carrier 68 can be formed as one component or separatecomponents that are connected together. In this example, the reversering gear 78 has peripheral tabs 80 that are received in peripheralrecesses 82 that are circumferentially spaced apart on the outer radiusof the forward carrier 68. The reverse ring gear 78 includes a radiallyinwardly facing gear surface 84.

The reverse planetary gearset 44 further includes a plurality of reverseplanet gears 86 that are rotatable about their own center axis 88 andthat are radially disposed between the reverse ring gear 78 and thereverse sun gear 74. Each reverse planet gear 86 has a radiallyoutwardly facing gear surface 90 that is engaged with the radiallyinwardly facing gear surface 84 of the reverse ring gear 78 and theradially outwardly facing gear surface 76 of the reverse sun gear 74.The reverse planetary gearset 44 also has a reverse carrier 92 thatretains the reverse planet gears 86 so that the reverse planet gears 86can rotate about their own center axis 88. The reverse carrier 92 isrotatable with respect to the reverse ring gear 78 and the reverse sungear 74. A reverse brake drum 94 is fixed to and rotates with thereverse carrier 92. The reverse brake drum 94 and reverse carrier 92 canbe formed as a single component or can be separate components that areconnected together. Pluralities of bearings 97, 99 (see FIGS. 10-12),such as roller bearings, support the reverse planetary gearset 44 withrespect to the output shaft 40.

Referring to FIGS. 7-9, the exact construction of the forward andreverse brakes 46, 48 can vary. In certain examples the forward andreverse brakes 46, 48 are conventional single-wrapped band brakes, asshown in FIG. 8. In certain examples the forward and reverse brakes 46,48 are conventional double-wrapped band brakes, as shown in FIG. 9. Thefunctionality of single-wrapped band brakes and double-wrapped bandbrakes generally is the same except the torque capability of thedouble-wrapped band brakes is higher than the single-wrapped band brakesfor the same actuation force. In the example of FIGS. 2-6, the forwardand reverse brakes 46, 48 are wrapped around and act on the forward andreverse brake drums 60, 94. Tightening the band brake prevents rotationof the brake drum. Loosening the band brake allows rotation of the brakedrum. FIG. 7 depicts one example wherein the forward brake 46 is adouble-wrapped band brake that is wrapped around the forward brake drum60. The reverse brake 48 and reverse brake drum 94 can be configured inthe same manner. An actuator 96 is configured to actuate the forward andreverse brakes 46, 48. The type of actuator can vary from that which isshown. In this example, the actuator 96 includes a servo-motor 98 thatmoves a pin 100 in the direction of arrow 102 against a bearing bracket104 disposed at one end of the forward brake 46. The other end of theforward brake 46 is fixed to a gearcase housing 106. Movement of the pin100 in the direction of arrow 102 tightens the forward brake 46 aboutthe brake drum 60, thus preventing the brake drum 60 from rotating. Inthis example, the forward and reverse brakes 46, 48 are self-energized,which means that the direction of rotation of the forward and reversebrake drums 60, 94 (as shown at arrow 103) is the same as the directionof actuation shown at arrow 102. Thus, rotation of the brake drums 60,94 assists actuation of the forward and reverse brakes 46, 48. Movementof the pin 100 opposite the direction of arrow 102 loosens the forwardbrake 46 with respect to the brake drum 60, thus allowing the brake drum60 to rotate.

Referring to FIGS. 10-12, the transmission 26 is able to engage theinput shaft 38 with the output shaft 40 in neutral, forward and reversegears. FIG. 10 shows the transmission 26 in neutral gear, whereinrotation of the input shaft 38 does not cause rotation of the outputshaft 40. In the neutral gear, neither of the brakes 46, 48 aretightened about the brake drums 60, 94. That is, the actuator 96 has notmoved the pin 100 in the direction of arrow 102. As such, both brakedrums 60, 94 are free to rotate. Thus forward rotation of the inputshaft 38 (shown at arrow 105) causes forward rotation of the reverse sungear 74 and forward ring gear 50. The forward rotation of the reversesun gear 74 causes reverse rotation of the reverse planet gears 86,which in turn causes forward rotation of the reverse carrier 92 andreverse brake drum 94. The forward rotation of the forward ring gear 50causes reverse rotation of the forward planet gears 62, which causesreverse rotation of the forward brake drum 60. The forward carrier 68and output shaft 40 remain stationary. The rotation of the input shaft38 is not translated to the output shaft 40.

FIG. 11 depicts the transmission 26 in forward gear, wherein the forwardbrake 46 is actuated by the actuator 96 so as to move the pin 100 in thedirection of arrow 102, which as described herein above, holds theforward brake drum 60 and forward sun gear 54 stationary. Forwardrotation of the input shaft 38 (at 105) causes forward rotation of theforward ring gear 50, which in turn causes forward rotation of theplurality of forward planet gears 62 and forward rotation of the forwardcarrier 68 and output shaft 40. The forward rotation of the reverse sungear 74 also results in reverse rotation of the plurality of reverseplanet gears 86 and forward rotation of the reverse carrier 92 andreverse brake drum 94.

FIG. 12 shows the transmission 26 in reverse gear, wherein the actuator96 moves the pin 100 in the direction of arrow 102, which as describedherein above, holds the reverse brake drum 94 and reverse carrier 92stationary. This prevents the plurality of reverse planet gears 86 fromrotating about the reverse sun gear 74. Forward rotation of the inputshaft 38 (at 105) causes forward rotation of the reverse sun gear 74,which causes reverse rotation of the plurality of reverse planet gears86 about their own center axis 88, which causes reverse rotation of thereverse ring gear 78, which in turn causes reverse rotation of theforward carrier 68 and the output shaft 40.

Thus rotation of the input shaft 38 simultaneously directly powers bothof the forward and reverse planetary gearsets 42, 44. More specifically,rotation of the input shaft 38 simultaneously, directly powers theforward planetary gearset 42 via the forward ring gear 50 and thereverse planetary gearset 44 via the reverse sun gear 74.

As shown in FIG. 2, a belt 108 connects the input shaft 38 to alubrication pump 110 for providing lubrication, e.g. oil, to thetransmission 26 and associated lower gearbox unit. Thus the lubricationpump 110 will operate any time that the engine 18 is operating. Acooling water pump 112 is directly connected to the input shaft 38 suchthat rotation of the input shaft 38 causes the cooling water pump 112 topump cooling water to the engine 18. Thus the cooling water pump 112will operate any time that the engine 18 is operating. Neither thelubrication pump 110 nor the cooling water pump 112 will change theiroperation based upon a change in gear implemented by the transmission26.

The components of the transmission 26 can be made of various materials,including metal, including steel and for example cast iron, whichdissipates heat.

Advantageously the transmission 26 can be configured to provide the samespeed reduction in both forward and reverse gears, have a high powerdensity compared to prior art.

Advantageously the transmission 26 can sustain specified torque input,speed, shift cycles and transient conditions such as wave jump, throttlechop, and/or the like and still be located between the driveshafthousing 24 and the gearcase housing 32, for example within a minimumaxial length, while still maintaining a hydrodynamic gearcase shape thatminimizes drag.

During continued research and development, the present inventors haverealized that the transmission arrangements described herein above withreference to FIGS. 1-12 can be controlled to purposefully, graduallyand/or partially and/or intermittently engage the respective band brakes46, 48. By doing so, the harshness (often referred to in the art as“shift clunk”) of the shift event can be softened, resulting in minimalnoise and vibration being transferred to the boat hull as compared totypical outboard marine engine. The present inventors have also realizedthat the transmission arrangements described herein above uniquely canbe controlled to purposefully create slip at the bandbrake-to-transmission drum interface. By doing so the speed of rotationof the output shaft 40 (which corresponds to the speed of rotation ofthe propulsor 34) can be reduced below that of the nominal speeddetermined by the transmission gear ratio. Advantageously, this providesthe ability to achieve low speeds (such as trolling speeds) that areless than the speeds that are determined by the transmission gear ratio.This also advantageously facilitates easier docking maneuvers byallowing a slower approach and less abrupt movements of the vessel, asthe operator toggles between forward, neutral and reverse gears tocontrol the vessel speed. The present inventors have also realized thatthis advantageously facilitates tighter holding (i.e. improvedmaneuvering) to a geographical set point in stationkeeping modes, ascompared to conventional control systems, which tend to overshoot setpoints. Based upon these realizations, the present inventors developedthe following systems and methods for controlling transmissions onmarine propulsion devices.

FIG. 13 depicts one example a system 200 for controlling transmissionactivity of a marine propulsion device, such as the marine propulsiondevice 10 described herein above. The system 200 includes theabove-described transmission 26 having the input shaft 38 that is driveninto rotation by the internal combustion engine 18 and the output shaft40 that drives the propulsor 34 into rotation. The transmission 26 alsoincludes the above-described forward and reverse planetary gearsets 42,44, which transfer power from the input shaft 38 to the output shaft 40.The forward and reverse band brakes 46, 48 are on the forward andreverse planetary gearsets 42, 44. As described herein above, actuationof each of the forward and reverse band brakes 46, 48 effects a gearchange amongst forward and reverse gears and neutral. The system 200also includes the noted shift actuator 96 (i.e. band brake actuator),which actuates the forward and reverse brakes 46, 48 to effect the notedgear change. The exact type of shift actuator 96 can include one or moreconventional electric, mechanical and/or hydraulically actuated devices.

The system 200 includes a computer controller 202 that is programmed tocontrol the shift actuator 96 to actuate the forward and reverse brakes46, 48 according to the programming structure and methods describedfurther herein below. The controller 202 is programmable and includes acomputer processor 204, computer software 206, a memory (i.e. computerstorage) 208, and one or more conventional computer input/output(interface) devices 209. The processor 204 loads and executes thesoftware 206 from the memory 208. Executing the software 206 controlsthe system 200 to operate as described in further detail herein below.The processor 204 can comprise a microprocessor and/or other circuitrythat receives and execute software 206 from memory 208. The processor204 can be implemented within a single device, but it can also bedistributed across multiple processing devices and/or subsystems thatcooperate in executing program instructions. Examples include generalpurpose central processing units, application specific processors, andlogic devices, as well as any other processing device, combinations ofprocessing devices, and/or variations thereof. The controller 202 can belocated anywhere with respect to the marine propulsion device 10 andmarine vessel 12 and can communicate with various components of thesystem 200 via wired and/or wireless links. The controller 202 can haveone or more microprocessors that are located together or remotely fromeach other in the system 200 or remotely from the system 200.

The memory 208 can include any storage media that is readable by theprocessor 204 and capable of storing the software 206. The memory 208can include volatile and/or nonvolatile, removable and/or non-removablemedia implemented in any method or technology for storage ofinformation, such as computer readable instructions, data structures,program modules, or other data. The memory 208 can be implemented as asingle storage device but may also be implemented across multiplestorage devices or subsystems. The memory 208 can further includeadditional elements, such as a controller that is capable ofcommunicating with the processor 204. Examples of storage media includerandom access memory, read only memory, magnetic discs, optical discs,flash memory discs, virtual and/or non-virtual memory, magneticcassettes, magnetic tape, magnetic disc storage, or other magneticstorage devices, or any other medium which can be used to store thedesired information and that may be accessed by an instruction executionsystem, as well as any combination or variation thereof, or any othertype of storage media. In some implementations, the storage media can bea non-transitory storage media.

The computer input/output devices 209 associated with the controller 202can include any one of a variety of conventional computer input/outputinterfaces for receiving electrical signals for input to the processorand for sending electrical signals from the processor to variouscomponents of the system 200. The controller 202, via the noted computerinput/output device 209, communicates with the band brake actuator 96via one or more communication links, which as mentioned herein above canbe wired or wireless links. As explained further herein below, thesystem 200 is capable of monitoring and controlling operationalcharacteristics of the marine propulsion device 10 by sending and/orreceiving control signals via one or more of the links shown in FIG. 13.Although the links are each shown as a single link, the term “link” canencompass one or a plurality of links that are each connected to one ormore of the components of the system 200.

The system 200 can include one or more operator input devices forinputting operator commands to the controller 202. The operator inputdevice(s) can include a joystick 210, throttle/shift lever 212, and/or amode selector 214, which can include for example a push button, switch,touch screen, or other device for inputting an instruction signal to thecontroller 202 from the operator of the of system 200. In certainexamples the operator input devices are operable to instruct thecontroller 202 to control the shift actuator 96 to thereby initiate anaction of the forward brake 46 or reverse brake 48 for example to enacta gear change amongst forward, neutral and reverse gears, as describedherein above. Such operator input devices for inputting operatorcommands to a controller are well known in the art and therefore forbrevity are not further herein described.

The system 200 can include one or more sensor(s) that are configured tosense “operational characteristics” of the system 200 and associatedmarine propulsion device 10 and convey such information in the form ofelectrical signals to the controller 202. The type of operationalcharacteristic can vary, and as explained further herein below caninclude actual speed of rotation of the input and/or output shafts 38,40; hydraulic pressure associated with the shift actuator 96; positionof the shift actuator 96 and/or band brakes 46, 48; an operational modeof the controller 202; an actual shift event; and/or the like.

In certain examples, the system 200 can include first and second speedsensors 218, 220 that are configured to directly or indirectly sensespeed of rotation of the input shaft 38 and output shaft 40,respectively, and communicate this information to the controller 202.The type and location of the speed sensors 218, 220 can vary and in someexamples are a Hall Effect or variable reluctance sensors located on ornear the input and output shafts 38, 40. Speed sensors are known in theart and commercially available, for example, from CTS Corporation orDelphi. The type and configuration of speed sensor can vary.

In certain examples where the band brake actuator 96 ishydraulically-operated, the system 200 can include a pressure sensor 222that is configured to sense the pressure of a hydraulic fluid thatoperates the band brake actuator 96 and then communicate thisinformation to the controller 202. The type and location of such apressure sensor 222 can vary and in some examples includes aconventional pressure transducer.

In certain examples, the system 200 can also include one or moreposition sensors 224 that are configured to sense the actual position ofthe shift actuator 96 and/or forward and/or reverse band brakes 46, 48and communicate this information to the controller 202. The type ofposition sensor can 224 can vary and can include for example aconventional photoeye and/or a conventional pressure transducer.

Advantageously, as described further herein below with reference toFIGS. 14-22, based upon one or more operational characteristic of themarine propulsion device 10, the controller 202 is programmed to controlthe band brake actuator 96 so that the rotational speed of the outputshaft 40 is less than the rotational speed of the input shaft 38 for acertain period of time, thus achieving the above-noted operationaladvantages of the system 200 over the prior art. The period of time canvary in duration based upon the particular operational characteristic ofthe marine propulsion device 10 and/or based upon the particular designof the system 200 and/or propulsion device 10. As stated above, thetype(s) of operational characteristic upon which the controller 202controls the forward and/or reverse band brakes 46, 48 to achieve thenoted speed differential can vary. The manner in which the controller202 controls the forward and/or reverse band brakes 46, 48 also canvary. Non-limiting examples of each are provided herein below.

FIGS. 14-16 depict operational behavior of the system 200 during typicalshifting amongst forward, reverse and neutral gears. FIG. 14 depicts thesystem 200 during a shift from neutral gear into forward gear. As shownat graph 230, the controller 202 controls the band brake actuator 96 toactuate the forward band brake 46 from zero to 100 percent output forceon the forward planetary gearset 42. Simultaneously, as shown at graph232, the controller 202 controls the band brake actuator 96 to cause thereverse band brake 44 to remain in the released state wherein zeropercent output force is applied to the reverse planetary gearset 44.FIG. 15 depicts the system 200 during a shift from neutral gear intoreverse gear. As shown at graph 236, the controller 202 controls theband brake actuator 96 to actuate the reverse band brake 48 from zero to100 percent output force on the reverse planetary gearset 44.Simultaneously, as shown at graph 234, the controller 202 controls theband brake actuator 96 to cause the forward band brake 46 to remain inthe released state wherein zero percent force is applied to the forwardplanetary gearset 42. FIG. 16 depicts the system 200 during a shift fromforward gear into neutral gear. As shown at graph 238, the controller202 causes the band brake actuator 96 to release the forward band brake46 from 100 percent output force to zero output force on the forwardplanetary gearset 42. Simultaneously, as shown at graph 240, thecontroller 202 controls the band brake actuator 96 to cause the reverseband brake 48 to remain in the released state wherein zero output forceis applied to the reverse planetary gearset 44. As would be understoodby one having ordinary skill in the art, during a shift from reversegear into neutral, the controller 202 causes the band brake actuator 96to release the reverse band brake 48 from 100% output force to zerooutput force on the reverse planetary gearset 44. Simultaneously, thecontroller 202 controls the band brake actuator 96 to cause the forwardband brake 46 to remain in the released state wherein zero output forceis applied to the forward planetary gearset 42.

FIG. 17-19 depict operational behavior of the system 200 during typicalin-gear, steady states. FIG. 17 depicts the system 200 during operationin forward gear. As shown at graphs 242 and 244, the controller 202controls the band brake actuator 96 to fully engage the forward bandbrake 46 and to maintain the reverse band brake 48 in the releasedstate. FIG. 18 depicts the system 200 during operation in reverse gear.As shown at graphs 246 and 248, the controller 202 controls the bandbrake actuator 96 to fully engage the reverse band brake 48 and tomaintain the forward band brake 46 in the released state. FIG. 19depicts the system 200 during operation in neutral gear. As shown atgraphs 250 and 252, the controller 202 controls the band brake actuator96 to maintain the forward band brake 46 and the reverse band brake 48in the released state.

FIG. 20 depicts the system 200 during a “trolling mode” of the marinepropulsion device 10 in forward gear, for example upon a request via oneor more of the operator input devices. “Trolling mode” is a term of artthat is used to describe a mode wherein the marine propulsion device isoperated at a consistent, relatively low speed. Marine propulsiondevices that control marine propulsion devices in trolling mode are welldefined in the prior art, including for example the incorporatedpublications that are listed in the Background section of the presentdisclosure. Thus the term “trolling mode” is not further describedherein for brevity sake. In certain examples according to the presentdisclosure, upon the request for trolling mode, the controller 202 isprogrammed to control the band brake actuator 96 to gradually actuatethe forward band brake 46 so that the band brake 46 is partially engagedwith the planetary gearset 42 and, as a result, the noted secondrotational speed of the output shaft 40 is maintained at a speed that isless than the nominal output speed. Nominal rotational speed for outputshaft 40 is rotational speed of input shaft 38 multiplied by the forwardplanetary gearset 42 gear ratio. With only partial engagement of bandbrake 46, the resultant rotational output speed is less than nominal.This is graphically shown by comparison of graphs 254 and 256. Gradualengagement of the forward band brake 46 with the forward brake drumresults in continual slip between the band brake and the brake drum(i.e. the band brake slips on the brake drum as the brake drum rotates).This slippage causes the rotational speed of the output shaft 40 to bemaintained at a speed that is less than the nominal.

In certain examples, the controller 202 can be configured to control theband brake actuator 96 so that the noted rotational speed of the outputshaft 40 is less than the rotational speed of the input shaft 38 by acertain amount, which can be stored in the memory 208. For example, thecontroller 202 can be programmed to control the force applied by bandbrake actuator 96 to the forward band brake 46 based upon how the speedof the input shaft 38 compares to the speed of the output shaft 40. If alarger speed differential between the input shaft 38 and the outputshaft 40 is desired, the controller 202 can be programmed to decreasethe force applied by the band brake actuator 96 on the forward bandbrake 46. If a smaller differential is desired, the controller 202 canbe programmed to increase the force applied by the band brake actuator96 on the forward band brake 46. As described above, the speed sensors218, 220 provide the controller 202 with the respective actual speeds ofrotation of the input and output shafts 38, 40.

FIG. 21 depicts the system 200 upon a request for “stationkeeping” ofthe marine propulsion device 10, via for example one or more of thenoted operator input devices. “Stationkeeping” is a term of art thatrepresents a mode of control of the marine propulsion device wherein themarine vessel is maintained at defined geographical position. Marinepropulsion systems that perform stationkeeping functionality are wellknown in the prior art, including for example the incorporatedpublications listed in the Background section of the present disclosure.Thus the term “stationkeeping” is not further described herein forbrevity. In certain examples according to the present disclosure, uponan operator request for stationkeeping mode, the controller 202 isprogrammed to control the band brake actuator 96, as shown at graph 258,to independently and gradually engage either and/or both of the forwardband brake 46 and reverse band brake 48 simultaneously or and/orseparately so as to provide better transition amongst forward, neutraland reverse gears and to quickly achieve and maintain rotational speedsof the output shaft 40 that are less than the minimum speed provided bythe gear ratio of the transmission 26.

FIG. 22 depicts one example of the system 200 during a shifting event.In this example, the controller 202 is programmed to control the bandbrake actuator 96 to reduce overall vessel speed and mitigate harshnessduring shifting and maneuvering. As shown at graph 260, the controller202 is programmed to control the band brake actuator 96 to continuouslyslip the interface between the band brake 46, 48 and the respective drum60, 94. In another example, shown at graph 262, the controller 202 isconfigured to control the band brake actuator 96 to actuate in aplurality of pulses that alternate between full engagement with the bandbrake 46, 48 and full disengagement with the planetary gearsets 42, 44so that the noted rotational speed of the output shaft 40 is less thanthe rotational speed of the input shaft 38. As shown in FIG. 22, thewidth of the pulses varies over time. In certain examples the width ofthe pulses can increase over time, thus providing a gradual increase inthe rotational speed of the output shaft 40. Providing high frequency,relatively short duration full engagement events can achieve the sameoverall vessel movement as providing continuous slip. Thisadvantageously can minimize slip and thus heat input to the brake bandto brake drum interface. Both of these methods can reduce overall vesselspeed and mitigate harshness during shifting and maneuvering.

FIG. 23 is one example of a flow chart depicting a method according tothe present disclosure for controlling a transmission system 200 for amarine propulsion device 10 having an internal combustion engine 18 thatdrives a propulsor 34. At step 300, the system 200 via for example anyone or more of sensors 218, 220, 222, 224, senses an operationalcharacteristic of marine propulsion device 10 and/or related system 200.At step 302, the controller 202 compares the operational characteristicto one or more values stored in the memory 208. Based upon thiscomparison, at step 304, the controller 202 is programmed to control theband brake actuator 96 in accordance with any one or more of theabove-described embodiments.

The present disclosure thus provides transmission systems and methodsfor marine propulsion devices having an internal combustion engine thatdrives a propulsor. In certain examples, the transmission systemcomprises: an input shaft that is driven into rotation at a non-zerofirst rotational speed by the internal combustion engine; an outputshaft that drives the propulsor into rotation at a non-zero secondrotational speed; a planetary gearset that transfers power from theinput shaft to the output shaft; a band brake on the planetary gearset,wherein actuation of the band brake effects a gear change in theplanetary gearset; a band brake actuator that actuates the band brake toeffect the gear change; and a controller that controls the band brakeactuator, wherein based upon at least one operational characteristic ofthe marine propulsion device the controller is programmed to control theband brake actuator so that the second rotational speed is less than thefirst rotational speed. In certain examples, based upon the operationalcharacteristic of the marine propulsion device, the controller isprogrammed to control the band brake actuator to gradually actuate theband brake so that the second rotational speed is less than the firstrotational speed. In certain examples, based upon the operationalcharacteristic of the marine propulsion device the controller isprogrammed to control the band brake actuator to gradually actuate theband brake so that a slip condition exists between the band brake andthe planetary gearset which causes the second rotational speed to beless than the first rotational speed. In certain examples, based uponthe operational characteristic of the marine propulsion device thecontroller is programmed to control the band brake actuator so as toactuate the band brake in a plurality of pulses that alternates betweenfull engagement of the band brake with the planetary gearset and fulldisengagement of the band brake with the planetary gearset which causesthe second rotational speed to be less than the first rotational speed.In certain examples, pulses in the plurality of pulses have differentlengths. In certain examples, the different lengths of the pulses in theplurality of pulses increase over time. The operational characteristiccan comprise an input to the controller of an operator request for atrolling mode of the marine propulsion device, an input to thecontroller of an operator request for stationkeeping mode of the marinepropulsion device, and/or a gear change in the planetary gearset.

In certain examples a first speed sensor senses and communicates thefirst rotational speed of the input shaft to the controller and a secondspeed sensor that senses and communicates the second rotational speed ofthe output shaft to the controller. The controller can be programmed tocontrol the band brake actuator so that the second rotational speed isless than the first rotational speed by a predetermined differentialamount stored in a memory of the controller.

In certain examples the band brake actuator is hydraulically actuated,and the system further comprises a pressure sensor that senses actualhydraulic pressure associated with the band brake actuator. Thecontroller can be programmed to control the band brake actuator basedupon how the actual hydraulic pressure compares to a predeterminedhydraulic pressure criteria stored in a memory of the controller.

The system can include a position sensor that senses an actual positionof the band brake. The controller can be programmed to control the bandbrake actuator based upon how the actual position of the band brakecompares to a predetermined positional criteria stored in a memory ofthe controller.

Advantageously the systems and methods herein disclosed can beimplemented with a single level planetary device instead of the duallevel planetary device shown in FIGS. 2-13.

In the above description, certain terms have been used for brevity,clarity, and understanding. No unnecessary limitations are to beinferred therefrom beyond the requirement of the prior art because suchterms are used for descriptive purposes and are intended to be broadlyconstrued. The different systems and method steps described herein maybe used alone or in combination with other systems and methods. It is tobe expected that various equivalents, alternatives and modifications arepossible within the scope of the appended claims.

What is claimed:
 1. A marine propulsion device comprising: an enginethat causes an input shaft to forwardly rotate at a non-zero firstrotational speed; an output shaft that is coupled to a propulsor suchthat rotation of the output shaft causes rotation of the propulsor; aplanetary gearset that couples the input shaft to the output shaft; aband brake actuator that actuates a band brake on the planetary gearset,wherein the band brake actuator is configured to apply a full forceengagement of the band brake on the planetary gearset and alternately toapply a less than full force engagement of the band brake on theplanetary gearset; wherein the full force engagement of the band brakeon the planetary gearset causes a gear change into at least one of aforward gear in which forward rotation of the input shaft causes forwardrotation of the output shaft, a reverse gear in which forward rotationof the input shaft causes reverse rotation of the output shaft, and aneutral gear in which rotation of the input shaft does not causerotation of the output shaft; wherein the less than full forceengagement of the band brake on the planetary gearset causes slip tooccur between the band brake and the planetary gearset, without causingthe gear change; and further wherein the slip causes the output shaft torotate at a non-zero second rotational speed that is less than a minimumnominal rotational speed that would otherwise result based on atransmission gear ratio of the planetary gearset; and a controllerconfigured to control the band brake actuator to mitigate harshnessduring the gear change by (A) initially applying the less than fullforce engagement of the band brake on the planetary gearset, therebycausing the slip to occur, and (B) thereafter applying the full forceengagement of the band brake on the planetary gearset, thereby causingthe gear change to occur.
 2. The marine propulsion device according toclaim 1, wherein the band brake actuator is hydraulically-actuated, andfurther comprising a pressure sensor that senses an actual hydraulicpressure associated with the band brake actuator, and wherein thecontroller controls the band brake actuator based upon how the actualhydraulic pressure compares to an amount stored in a memory of thecontroller.
 3. The marine propulsion device according to claim 1,further comprising a position sensor that senses an actual position ofthe band brake, wherein the controller controls the band brake actuatorto achieve the non-zero second rotational speed based upon how theactual position of the band brake compares to a value stored in a memoryof the controller.
 4. The marine propulsion device according to claim 1,the controller is programmed to control the band brake actuator togradually actuate the band brake from a zero force engagement of theband brake on the planetary gearset up to the full force engagement ofthe band brake on the planetary gearset.
 5. A marine propulsion devicecomprising: an engine that causes an input shaft to forwardly rotate ata non-zero first rotational speed; an output shaft that is coupled to apropulsor such that rotation of the output shaft causes rotation of thepropulsor; a planetary gearset that couples the input shaft to theoutput shaft; a band brake on the planetary gearset; a band brakeactuator that actuates the band brake, wherein actuation of the bandbrake causes a gear change into at least one of a forward gear in whichforward rotation of the input shaft causes forward rotation of theoutput shaft, a reverse gear in which forward rotation of the inputshaft causes reverse rotation of the output shaft, and a neutral gear inwhich rotation of the input shaft does not cause rotation of the outputshaft; a controller configured to control the band brake actuator tomitigate harshness during the gear change by (A) initially actuating theband brake in a plurality of pulses that alternate between a full forceengagement of the band brake on the planetary gearset and a zero forceengagement of the band brake on the planetary gearset, which therebycauses the output shaft to rotate at a non-zero rotational speed that isless than a minimum nominal rotational speed that would otherwise resultbased on a transmission gear ratio of the planetary gearset, and (B)thereafter actuating the band brake so as to apply the full forceengagement of the band brake on the planetary gearset, thereby causingthe gear change to occur.
 6. The marine propulsion device according toclaim 5, wherein each pulse in the plurality of pulses has a differentlength than other pulses in the plurality of pulses.
 7. The marinepropulsion device according to claim 6, wherein the lengths of thepulses in the plurality of pulses increase over time.
 8. A method ofcontrolling a transmission in a marine propulsion device, the methodcomprising: providing an engine that causes forward rotation of an inputshaft at a non-zero first rotational speed; providing a planetarygearset that couples the input shaft to an output shaft such thatrotation of the input shaft causes rotation of the output shaft, whichin turn causes rotation of a propulsor; initially actuating a band brakeon the planetary gearset at less than full force so that slip occursbetween the band brake and the planetary gearset, without causing a gearchange, wherein the slip causes the output shaft to rotate at a non-zerosecond rotational speed that is less than a minimum nominal rotationalspeed that would otherwise result based on a transmission gear ratio ofthe planetary gearset; and thereafter actuating the band brake at fullforce so as to cause the gear change; wherein initial actuation of theband brake at less than full force causes the output shaft to rotate ata non-zero second rotational speed and thus mitigates harshness duringthe gear change.
 9. The method according to claim 8, wherein the bandbrake is initially actuated by gradually increasing the band brake froma zero force engagement on the planetary gearset to the full forceengagement of the band brake on the planetary gearset.
 10. A method ofcontrolling a transmission in a marine propulsion device, the methodcomprising: providing an engine that causes forward rotation of an inputshaft at a non-zero first rotational speed; providing a planetarygearset that couples the input shaft to an output shaft such thatrotation of the input shaft causes rotation of the output shaft, whichin turn causes rotation of a propulsor; initially actuating a band brakeon the planetary gearset in a plurality of pulses that alternate betweenfull engagement of the band brake on the planetary gearset and a zeroforce engagement of the band brake on the planetary gearset; andthereafter actuating the band brake at full force so as to cause a gearchange, wherein initial actuation of the band brake in the plurality ofpulses causes the output shaft to rotate at a non-zero second rotationalspeed and thus mitigates harshness during the gear change.
 11. Themethod according to claim 10, wherein each pulse in the plurality ofpulses has a different length than other pulses in the plurality ofpulses.
 12. The method according to claim 11, wherein the lengths of thepulses in the plurality of pulses increase over time.